title: Early inflammatory reactions in atherosclerosis are induced by proline-rich tyrosine kinase/reactive oxygen species-mediated release of tumor necrosis factor-alpha and subsequent activation of the p21Cip1/Ets-1/p300 system.
abstract: OBJECTIVE
  Reactive oxygen species (ROS) are involved in the initial process of atherosclerosis, whereas it remains to be determined how atherogenic stimulus causes ROS-mediated proinflammatory reactions. Here, we focused on proline-rich tyrosine kinase (PYK2)-mediated ROS generation and examined how atherogenic stimulus causes early proinflammatory reactions.
  
  
  RESULTS
  PYK2-deficient (knockout [KO]) (PYK2-KO) mice were crossbred with apolipoprotein E (ApoE)-deficient (PYK2-KO/ApoE-KO) mice. PYK2-KO/ApoE-KO mice and endothelial cells (EC) were used for the study. Aortic atherogenic lesions in PYK2-KO/ApoE-KO mice were markedly decreased (55% versus ApoE-KO) after 8 weeks of a Western diet. Aortic PYK2 was activated as early as 7 days after the Western diet, when inflammatory cells were not yet activated. Addition of the proatherogenic oxidized phospholipid lysophosphatidylcholine caused activation of endothelial PYK2. Lysophosphatidylcholine-activated PYK2 induced NADPH oxidase-mediated ROS generation and ROS-mediated synthesis of tumor necrosis factor-α (TNFα), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemotactic protein-1 (MCP-1), and p21Cip1/Ets-1. Neutralizing anti-TNFα antibody or knockdown of p21Cip1/Ets-1 system blocked the induction of VCAM-1 and MCP-1. PYK2 deficiency abolished these ROS-mediated proinflammatory reactions. Further analysis revealed that PYK2/ROS-mediated p21Cip1/Ets-1 activation upregulated the transcription of the MCP-1 gene in collaboration with p300 transcription coactivator.
  
  
  CONCLUSIONS
  PYK2 is a key tyrosine kinase activated by high cholesterol exposure, which causes ROS-mediated TNFα release and induces TNFα-dependent expression of proinflammatory molecules via the p21Cip1/Ets-1/p300 transcription system.
authors.affiliation: Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Katsume
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Okigaki
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsui
authors.forename: Jishan
authors.initials: J
authors.lastname: Che
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Adachi
authors.forename: Eigo
authors.initials: E
authors.lastname: Kishita
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Ikeda
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ueyama
authors.forename: Satoaki
authors.initials: S
authors.lastname: Matoba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsubara
mesh_terms: D000818:Animals; D001018:Aortic Diseases / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D050197:Atherosclerosis / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D016026:Bone Marrow Transplantation; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000201:enzymology* / Q000473:pathology; D051418:Focal Adhesion Kinase 2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006937:Hypercholesterolemia / Q000201:enzymology / Q000235:genetics; D018836:Inflammation Mediators / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000378:metabolism; D050784:Proto-Oncogene Protein c-ets-1 / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001057:Apolipoproteins E; C491768:Ccl2 protein, mouse; C493957:Cdkn1a protein, mouse; D018932:Chemokine CCL2; D050759:Cyclin-Dependent Kinase Inhibitor p21; C494042:Ets1 protein, mouse; D018836:Inflammation Mediators; D008077:Lipoproteins, LDL; D008244:Lysophosphatidylcholines; D050784:Proto-Oncogene Protein c-ets-1; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; C099252:oxidized low density lipoprotein; D019255:NADPH Oxidases; D050880:p300-CBP Transcription Factors; D051418:Focal Adhesion Kinase 2; C496053:Ptk2b protein, mouse